The objectives of this work were to evaluate the productive and reproductive efficiencies and also the genetics parameters for traits considered, using data from 1877 crossbreed cows (Holstein x Zebu) from four genetics groups. The cows belonged to three commercial dairy herds monitored from 1989 to 1998 by the Dairy Information System (DAISY). The data were processed using the procedure available in SAS (Statistical Analysis System), while genetic parameters on productive and reproductive traits were estimated by the multiple trait derivative-free restricted maximum likelihood method (MTDFREML). Effects of genetic group and calving year were significant for age at first calving (AFC), interval from calving to first service (ICFS), lactation length (LL), milk production (MY) and milk production per day of calving interval (MYCI). The estimates of heritability (h²) for all reproductive traits were near zero in agreement with others studies indicating that these traits are mostly determined by management practices. The h² estimates for milk yield (MY) were 0.28, this means that the additive genetic variance is middle. The genetic correlations (r g) between MY and LL of 0.81 could be considered high.
genetic parameters; dairy cattle; crossbreed cows
